997 resultados para Clark, William, 1770-1838.
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High bone mass (HBM) can be an incidental clinical finding; however, monogenic HBM disorders (eg, LRP5 or SOST mutations) are rare. We aimed to determine to what extent HBM is explained by mutations in known HBM genes. A total of 258 unrelated HBM cases were identified from a review of 335,115 DXA scans from 13 UK centers. Cases were assessed clinically and underwent sequencing of known anabolic HBM loci: LRP5 (exons 2, 3, 4), LRP4 (exons 25, 26), SOST (exons 1, 2, and the van Buchem's disease [VBD] 52-kb intronic deletion 3'). Family members were assessed for HBM segregation with identified variants. Three-dimensional protein models were constructed for identified variants. Two novel missense LRP5 HBM mutations ([c.518C>T; p.Thr173Met], [c.796C>T; p.Arg266Cys]) were identified, plus three previously reported missense LRP5 mutations ([c.593A>G; p.Asn198Ser], [c.724G>A; p.Ala242Thr], [c.266A>G; p.Gln89Arg]), associated with HBM in 11 adults from seven families. Individuals with LRP5 HBM ( approximately prevalence 5/100,000) displayed a variable phenotype of skeletal dysplasia with increased trabecular BMD and cortical thickness on HRpQCT, and gynoid fat mass accumulation on DXA, compared with both non-LRP5 HBM and controls. One mostly asymptomatic woman carried a novel heterozygous nonsense SOST mutation (c.530C>A; p.Ser177X) predicted to prematurely truncate sclerostin. Protein modeling suggests the severity of the LRP5-HBM phenotype corresponds to the degree of protein disruption and the consequent effect on SOST-LRP5 binding. We predict p.Asn198Ser and p.Ala242Thr directly disrupt SOST binding; both correspond to severe HBM phenotypes (BMD Z-scores +3.1 to +12.2, inability to float). Less disruptive structural alterations predicted from p.Arg266Cys, p.Thr173Met, and p.Gln89Arg were associated with less severe phenotypes (Z-scores +2.4 to +6.2, ability to float). In conclusion, although mutations in known HBM loci may be asymptomatic, they only account for a very small proportion ( approximately 3%) of HBM individuals, suggesting the great majority are explained by either unknown monogenic causes or polygenic inheritance.
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The rapid disruption of tropical forests probably imperils global biodiversity more than any other contemporary phenomenon(1-3). With deforestation advancing quickly, protected areas are increasingly becoming final refuges for threatened species and natural ecosystem processes. However, many protected areas in the tropics are themselves vulnerable to human encroachment and other environmental stresses(4-9). As pressures mount, it is vital to know whether existing reserves can sustain their biodiversity. A critical constraint in addressing this question has been that data describing a broad array of biodiversity groups have been unavailable for a sufficiently large and representative sample of reserves. Here we present a uniquely comprehensive data set on changes over the past 20 to 30 years in 31 functional groups of species and 21 potential drivers of environmental change, for 60 protected areas stratified across the world's major tropical regions. Our analysis reveals great variation in reserve `health': about half of all reserves have been effective or performed passably, but the rest are experiencing an erosion of biodiversity that is often alarmingly widespread taxonomically and functionally. Habitat disruption, hunting and forest-product exploitation were the strongest predictors of declining reserve health. Crucially, environmental changes immediately outside reserves seemed nearly as important as those inside in determining their ecological fate, with changes inside reserves strongly mirroring those occurring around them. These findings suggest that tropical protected areas are often intimately linked ecologically to their surrounding habitats, and that a failure to stem broad-scale loss and degradation of such habitats could sharply increase the likelihood of serious biodiversity declines.
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The high species richness of tropical forests has long been recognized, yet there remains substantial uncertainty regarding the actual number of tropical tree species. Using a pantropical tree inventory database from closed canopy forests, consisting of 657,630 trees belonging to 11,371 species, we use a fitted value of Fisher's alpha and an approximate pantropical stem total to estimate the minimum number of tropical forest tree species to fall between similar to 40,000 and similar to 53,000, i.e., at the high end of previous estimates. Contrary to common assumption, the Indo-Pacific region was found to be as species-rich as the Neotropics, with both regions having a minimum of similar to 19,000-25,000 tree species. Continental Africa is relatively depauperate with a minimum of similar to 4,500-6,000 tree species. Very few species are shared among the African, American, and the Indo-Pacific regions. We provide a methodological framework for estimating species richness in trees that may help refine species richness estimates of tree-dependent taxa.
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In recent times, several new species of amphibians have been described from India. Many of these discoveries are from biodiversity hotspots or from within protected areas. We undertook amphibian surveys in human dominated landscapes outside of protected areas in south western region of India between years 2013-2015. We encountered a new species of Microhyla which is described here as Microhyla laterite sp. nov. It was delimited using molecular, morphometric and bioacoustics comparisons. Microhyla laterite sp. nov. appears to be restricted to areas of the West coast of India dominated by laterite rock formations. The laterite rock formations date as far back as the Cretaceous-Tertiary boundary and are considered to be wastelands in-spite of their intriguing geological history. We identify knowledge gaps in our understanding of the genus Microhyla from the Indian subcontinent and suggest ways to bridge them.
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La obra publicada hacia fines del siglo XIX por el Comodoro Antonio Somellera (1812-1889) bajo el nombre Recuerdos de una víctima de la Mazorca, es un valiosísimo documento histórico para analizar los hechos e ideas que determinaron muchos de los aspectos de la vida política del momento al que se refiere, el gobierno de Juan Manuel de Rosas en Buenos Aires durante 1838-1840. Allí se expresa cabalmente uno de los elementos más controvertidos de la historia del país: la violencia política, tanto física como discursiva, a que estaban acostumbrados todos los hombres que dirigían, ya sea como gobierno o como oposición, los destinos de la Argentina. A través de un análisis contextualizado y profundo de estas Memorias, el presente trabajo buscará dilucidar algunos de los aspectos estructurales que caracterizaron la realidad política de esos años.
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Desde 1945 la izquierda argentina no pudo resolver el enigma planteado por el hecho de que la clase obrera era peronista. Varios intentos teóricos fracasaron antes de que John William Cooke hiciera el suyo a mediados de los años sesenta. Influenciado por Gramsci, consideró que la clase obrera es una categoría histórica, por lo que el peronismo era la experiencia histórica de la clase obrera argentina y, como tal, revolucionario. Neutralizó el papel político de Perón convirtiéndolo en el símbolo de la identidad peronista. Por esto, la teoría de Cooke fue clave para que guerrilleros de izquierda se declararan peronistas sin que les importaran las opiniones e intenciones políticas de Perón. Las limitaciones de esa teoría quedaron expuestas cuando el general regresó a la Argentina y fue electo presidente por tercera vez.
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Ponencia leída en el Foro de Comunicaciones IkasArt II (BEC Barakaldo, 2010.06.17)
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Parte 1 - Leis
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Hablar del papel de las colonias y del comercio en los siglos XVIII y XIX del País Vasco es un ciclo sobre Dirección y Administracion de empresas parece un tanto fuera de lugar. Problamenente muchos alumnos y sectores del profesorado no suelen tener muy claro para qué sirve una materia como la historia y más en concreto la historia económica. Sin embargo la Historia en general y la económia en particular cumplen o mejor, deberían cumplir un papel importante y sobre todo deberían ser tenidas en cuenta a la hora de tomar decisiones tanto a nivel micoeconómico como macroeconómico.
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This synopsis of the literature was designed to summarize the biological and biochemical studies involving Pandalus borealis as well as to provide a summary of the literature regarding the fisheries data published before early 1984. Included are many unpublished observations, drawn from studies at the State of Maine Department of Marine Resources Laboratory in West Boothbay Harbor, Maine. (PDF file contains 63 pages.)
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This report describes FORTH software written for several instruments used in the NASA-sponsored project to design and build Marine Optical Buoy System (MOBS) and in the NOAA-sponsored project "EOS MODIS Execution: Oceanographic Profiling, Data Acquisition and Management for the Marine Optical Buoy System·'. In the NOAA project MLML and NOAA personnel will participate in quarterly cruises at the MOBS Hawaiian site to validate performance of SeaWiFS and will participate in several extended "process" cruises to provide wide geographic surface truthing investigations similar to those lead by Dennis Clark (NOAA) following the "launch of CZCS in 1979. In the NASA project we are designing and building MOBS, a high resolution spectroradiometer that will operate autonomously in a buoy moored west of Lanai in the Hawaiian Islands. That instrument, the "Marine Optical System" (MOS), will transmit by cellular phone in near real time observations of upwelled radiance and downwelled irradiance from three depths. [PDF contains 90 pages]